Device for spreading and distributing particles on a material web

ABSTRACT

Apparatus is disclosed for spreading and distributing particles such as glue-coated wood fibers onto a moving web including rotatable axles disposed transverse to the direction of movement of the moving web with each axle including a number of distributors rotatable with the axles and disposed generally obliquely with respect to the axes of the axles, each of the axles disposed at successively increasing heights from the moving web in its direction of movement whereby each of the distributors extends into the wood fiber particles comprising the moving web and distributes the particles across the moving web.

FIELD OF THE INVENTION

The present invention relates to apparatus for spreading anddistributing particles on a material web, such as glue-coated woodfibers on a wire or a conveying belt for production of wood-fiberboards.

BACKGROUND OF THE INVENTION

In a forming station for producing wood-fiber boards there is currentlya need to distribute glue-coated wood fibers on a wire or a conveyingbelt to form a layer with a certain thickness. The layer of wood fibersis transported by the wire or conveying belt to a pressing plant, inwhich the wood fibers, under the influence of pressure and temperature,are pressed together into a continuous board.

As is shown in International Application No. PCT/SE95/01402, a device ofthe type described above is previously known, whose purpose is theleveling of the material web after air distribution of the particles.Another type of leveling or milling is disclosed in U.S. Pat. No.5,496,570 and consists of a scraper or a planing device, which, for themethod shown, cut off any excess of the wood fibers. A disadvantage withthe known technique is that a large amount of wood fibers arerecirculated to the process from the leveling or milling step, which. isunfavorable, since the quality deteriorates by wear.

U.S. Pat. No. 5,496,570 shows how a number of disc rollers are used fordistributing wood fibers and for pulverizing possible clumps among thewood fibers. A similar device, for distributing wood fibers with the aidof disc rollers, is shown in Swedish Patent No. 436,627. A commonelement in both of these latter references is that the disc rollers arelocated above the level of the wood fibers and by utilizing successivelydifferent distances between the discs of the different disc rollers, onemay achieve sorting and orientation of the wood fibers in severaldifferent layers. A disadvantage, however, is that the distribution isunsatisfactory across the material web.

An object of the present invention is to thus provide a homogenous layerof wood fibers, having a desired distribution over the width of thematerial web. Another object is to provide a distribution of the woodfibers, in such way that any considerable subsequent leveling or millingis thereby avoided.

SUMMARY OF THE INVENTION

In accordance with the present invention, this and other objects havenow been realized by the discovery of apparatus for spreading anddistributing particles onto a moving web of the particles carried by amoving belt and moving in a predetermined direction, the apparatuscomprising a plurality of rotatable axles disposed transverse to thepredetermined direction, each of the plurality of rotatable axlesincluding a plurality of distributors rotatable with the correspondingplurality of rotatable axles and disposed generally obliquely withrespect to the plurality of rotatable axles, each of the plurality ofrotatable axles disposed at successively increasing heights from themoving web in the predetermined direction, whereby each of the pluralityof distributors extends into the particles comprising the moving web anddistributes the particles across the moving web. Preferably, theparticles comprise glue-coated wood fibers for production of woodfiberboard.

In accordance with one embodiment of the apparatus of the presentinvention, the apparatus includes a common frame, each of the pluralityof rotable axles being attached to the common frame, and the commonframe being disposed at a predetermined angle with respect to the movingweb, whereby each of the plurality of rotatable axles provides a layerof the particles having a predetermined thickness, the predeterminedthickness being determined by the predetermined angle of the commonframe. In a preferred embodiment, the common frame is adjustable in adirection transverse to the predetermined direction at a predeterminedtransverse angle, whereby the cross-sectional profile of the particlescomprising the moving web can be altered by altering the predeterminedtransverse angle.

In accordance with another embodiment of the apparatus of the presentinvention, each of the plurality of rotatable axles is individuallyvertically adjustably attached to the common frame, whereby thepredetermined thickness of each of the layers of the particles can beadjusted.

In accordance with another embodiment of the apparatus of the presentinvention, each of the plurality of rotatable axles is individuallylongitudinally adjustably attached to the common frame, whereby thedistance between the plurality of rotatable axles can be altered so asto alter the angle between the plurality of rotatable axles and thedistribution of the particles within the layers.

In accordance with another embodiment of the apparatus of the presentinvention, at least one of the plurality of distributors comprises anelliptical disk. Preferably, the elliptical disk includes at least oneopening, whereby the particles can pass therethrough. In a preferredembodiment, the elliptical disk includes a plurality of the openings,and includes at least one spoke separating the plurality of openings.Preferably, the at least one spoke is shaped in a manner whereby theparticles are transported by the at least one shaped spoke in a desireddirection.

In accordance with one embodiment of the apparatus of the presentinvention, at least one of the distributors includes transport meansdisposed on the periphery thereof, whereby the particles are transportedin a desired direction by the transport means. Preferably, the transportmeans comprises protrusions.

In accordance with another embodiment of the apparatus of the presentinvention, at least one of the distributors comprises an elliptical diskincluding at least one recess, the elliptical disk formed in a mannerwhereby the particles are transported in a desired direction thereby.

In accordance with another embodiment of the apparatus of the presentinvention, at least one of the distributors comprises an elliptical diskincluding corrugations, whereby the particles are transported in adesired direction thereby.

In accordance with another embodiment of the apparatus of the presentinvention, at least one of the distributors comprises a plurality ofprotruding members, whereby the particles are transported in a desireddirection thereby. Preferably, the protruding members are disposed inthe shape of an elliptical planar brush. In a preferred embodiment, theprotruding members comprises a plurality of protruding pins.

These objects of the present invention are achieved with a device whichis characterized in that several axles, with distributing means, arearranged successive after each other at an increasing height, and arearranged such that the distribution means extends down into the materialweb, whereas particles at each axle, by the rotation of the distributionmeans, will be spread across the material web.

IIn a preferred embodiment of the present invention, the axles aresecured to a common frame, which is arranged at an angle against thematerial web such that several layers are formed above each other,whereby the thickness of these layers, and thus the thickness of theresulting material web, is defined by this angle.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail referring to the followingdetailed description with reference to the accompanying drawings, inwhich;

FIG. 1 is a side, elevational, schematic view of a forming station forwood fiber board;

FIG. 2 is a front, perspective, schematic view of a device according tothe present invention;

FIG. 3 is a front, elevational, partial, schematic view of a formingroller for use in accordance with the present invention;

FIG. 4 is a side, perspective, schematic view of several forming rollersarranged according to the present invention;

FIG. 5 is a side, elevational, schematic view of an alternativeembodiment of a distribution means according to the present invention;

FIG. 6 is a side, elevational, schematic view of another embodiment of adistribution means according to the present invention;

FIG. 7 is a side, elevational, schematic view of another embodiment of adistribution means according to the present invention;

FIG. 8 is a side, elevational, schematic view of another embodiment of adistribution means according to the present invention; and

FIG. 9 is a front, elevational, schematic view of another embodiment ofa distribution means mounted on an axle according to the presentinvention.

DETAILED DESCRIPTION

Referring to the drawings, FIG. 1 shows a forming station for wood fiberboards, comprising a cyclone 1, for supply of glue-coated wood fibers.Wood fibers are discharged through a sluice 2 to a dosing bin 3, fordosage of wood fibers. The dosing bin 3 has means 4 for feeding woodfibers to a conveyor scale 5. After the conveyor scale 5 the wood fiberspass a spreader 6, which can be provided with wings, discs, pins orother known means for disintegrating the wood fibers and distributingthem over a number of forming rollers 7. The forming rollers 7 can beadjusted to different angles, depending on the desired thickness of thelayer of wood fibers. The forming rollers 7 feed wood fibers on a wire 8or a conveyor belt for transportation to a pressing station (not shown).The drawings show how the devices for supply of wood fibers, up to theforming rollers 7, are located in line with the wire 8 or conveyor belt,but, the devices may also be located such that the supply of wood fibersare performed perpendicularly with respect to the wire 8 or conveyingbelt.

FIG. 2 shows a more detailed view of the spreaders 6, followed by theforming rollers 7 and the material web 9 discharged on the wire 8 orconveyor belt. The forming rollers 7 are secured to a common frame 10,which is arranged at an angle α with respect to the material web 9.

FIG. 3 shows a forming roller 7, which is arranged transverse to thedirection of movement of the material web, and comprises a rotating axle11 and a number of distributing means 12. The distributing means 12 arelocated along axle 11 and consist, in a first preferred embodiment, of anumber of oblique, essentially elliptical discs, or similar disc shapedmeans, which rotate with the axle 11. The distributing means 12 extenddown into the material web 9.

The expression oblique discs also embraces discs which, in fact, arearranged straight on the axle, but which by bending or the like have atleast one resulting oblique surface acting on the material web 9.

The axle 11 and the distribution means 12 can be of the type, asdisclosed in International Patent Application No. PCT/SE95/01402, inwhich the distribution means 12 are mounted an axial distance from eachother for rotation together with the axle 11, and, around its shorterdiameter, are arranged obliquely in relation to the axle 11, in such away that they have a circular axial projection. In addition, thedistribution means 12 are mounted, in such a way, that the axialdistance between adjacent discs overlaps each other in the axialdirection, and in addition the discs are inclined at an angle of fromabout 45° to 80°, and preferably about 60° in relation to the axle 11.During rotation the discs 12 perform an axially backwards and forwardsthrowing movement of wood fibers inside a imaginary horizontal straighttube.

FIG. 4 shows several axles 11 a-11 f arranged successively after eachother at increasing heights from the bottom of the material web 9, andarranged such that the distribution means 12 of the axis projectessentially down into the material web 9. Thus, the particles at eachaxle, 11 a-11 f, will, by rotation of the distribution means 12, spreadacross the material web 9 to an even layer, 13 a-13 f, of homogenousdistributed particles.

FIG. 5 shows a second alternative embodiment of a distributing means 12,which consists of an elliptical disc provided with openings 14, throughwhich wood fibers can be transported. The openings 14 can be of asuitable form, but are preferably shaped like spokes 15 or similar meansformed between the openings 14. The spokes 15 can also be turned orshaped in another suitable manner, such that some action by propeller iscreated, for transportation of wood fibers in a desired direction. Thedisc can also be provided with protrusions or similar means along itsperiphery to effect such transportation.

FIG. 6 shows a third alternative embodiment of a distributing means 12,in which, an elliptical disc is provided with recesses to form apropeller blade 16 or similar means, by which wood fibers can betransported in a desired direction. Thus, the distributing means 12according to this embodiment extend only partly around the axle 11. Itis also possible to alter the shape of different distributing means 12,according to this embodiment, to provide different properties along theaxle 11, in such a way that a desired distribution is obtained.

FIG. 7 shows a fourth alternative embodiment of a distributing means 12,in which an elliptical disc is provided with corrugations 17 or similarsurface structure, to convey the wood fibers. The corrugations 17 canalso be shaped in such a way that some propeller-type action is createdfor transportation of the wood fibers in a desired direction.

FIG. 8 shows a fifth alternative embodiment of a distributing means 12,in which, a number of protruding pins 18 or similar structure forms anelliptical planar brush, to convey the wood fibers.

FIG. 9 shows a sixth alternative embodiment of a distributing means 12,in which, propeller blades, 19A-19D, or similar means are arranged alongan axle 11, which in this embodiment has a rectangular cross-section.The outer edge 20 of two propeller blades, 19A and 19B, and, 19C and19D, respectively, located on opposite sides, 21A and 21B, and, 21C and21D, respectively, of the axle 11, extend along a common ellipticalpath. In this embodiment the elliptical path of the propeller blades,19A and 19B, are arranged at an angle with respect to the ellipticalpath of the propeller blades, 19C and 19D.In this manner, it is possibleto locate the distribution means 12 closer, and it is also possible toalter the shape of different distributing means 12, according to thisembodiment, to achieve different properties along the axle 11, in such away that a desired distribution is obtained.

The axles, 11 a-11 f, are arranged at an angle with respect to thematerial web 9, in such a way that several layers, 13 a-13 f, are formedabove each other, the thickness of these layers, and thus the thicknessof the resulting material web 9 will be defined by that angle.

In the figures the distribution means 12 are directed in the samedirection for the different axles 11, but within the framework of thepresent invention, they may also be directed in different directions.

It is also possible to adjust the inclination of the frame 10 at anangle transverse to the material web 9, in such a way that the resultingcross-sectional profile of the material web will have a desired shape.By securing the axles, 11 a-11 f, in the frame 10, in an adjustablemanner, in which each axle, 11 a-11 f, is individually adjustablevertically, it is possible to influence the thickness of respectivelayers, 13 a-13 f. This is especially important for the uppermostlocated forming roller, to influence the thickness of the uppermostlayer 13 f.

Naturally, the axles, 11 a-11 f, may also be displaced individually,longitudinally of the material web, to provide different distancesbetween said axles, 11 a-11 f, or an inclination of respective axles, 11a-11 f, and by that influence the distribution of the wood fibers withinrespective layers, 13 a-13 f.

An additional opportunity to influence the distribution of the woodfibers within respective layer, 13 a-13 f, is that the axles, 11 a-11 f,are themselves individually adjustable. Thus, each axle, 11 a-11 f, isshaped, in a known manner, such that the axle during operation has adeflection in a certain direction.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

What is claimed is:
 1. Apparatus for spreading and distributingparticles onto a moving web of said particles carried by a moving beltand moving in a predetermined direction, said apparatus comprising aplurality of rotatable axles disposed transverse to said predetermineddirection, each of said plurality of rotatable axles including aplurality of distributors rotatable with said corresponding plurality ofrotatable axles and disposed generally obliquely with respect to saidplurality of rotatable axles, each of said plurality of rotatable axlesdisposed at successively increasing heights from said moving web in saidpredetermined direction, whereby each of said plurality of distributorsextends into said particles comprising said moving web and distributessaid particles across said moving web.
 2. The apparatus of claim 1wherein said particles comprise glue-coated wood fibers for productionof wood fiberboard.
 3. The apparatus of claim 1 including a commonframe, each of said plurality of rotatable axles being attached to saidcommon frame, said common frame being disposed at a predetermined anglewith respect to said moving web, whereby each of said plurality ofrotatable axles provides a layer of said particles having apredetermined thickness, said predetermined thickness being determinedby said predetermined angle of said common frame.
 4. The apparatus ofclaim 3 wherein said common frame is adjustable in a directiontransverse to said predetermined direction at a predetermined transverseangle, whereby the cross-sectional profile of said particles comprisingsaid moving web can be altered by altering said predetermined transverseangle.
 5. The apparatus of claim 3 wherein each of said plurality ofrotatable axles is individually vertically adjustably attached to saidcommon frame, whereby said predetermined thickness of each of saidlayers of said particles can be adjusted.
 6. The apparatus of claim 3wherein each of said plurality of rotatable axles is individuallylongitudinally adjustably attached to said common frame, whereby thedistance between said plurality of rotatable axles can be altered so asto alter the angle between said plurality of rotatable axles and thedistribution of said particles within said layer.
 7. The apparatus ofclaim 1 wherein at least one of said plurality of distributors comprisesan elliptical disk.
 8. The apparatus of claim 7 wherein said ellipticaldisk includes at least one opening, whereby said particles can passtherethrough.
 9. The apparatus of claim 8 wherein said elliptical diskincludes a plurality of said openings, and including at least one spokeseparating said plurality of openings.
 10. The apparatus of claim 9wherein said at least one spoke is shaped in a manner whereby saidparticles are transported by said at least one shaped spoke in apredetermined direction.
 11. The apparatus of claim 1 wherein at leastone of said distributors includes transport means disposed on theperiphery thereof, whereby said particles are transported in apredetermined direction by said transport means.
 12. The apparatus ofclaim 11 wherein said transport means comprises protrusions.
 13. Theapparatus of claim 1 wherein at least one of said distributors comprisesan elliptical disk including at least one recess, said elliptical diskformed in a manner whereby said particles are transported in apredetermined direction thereby.
 14. The apparatus of claim 1 wherein atleast one of said distributors comprises an elliptical disk includingcorrugations, whereby said particles are transported in a predetermineddirection thereby.
 15. The apparatus of claim 1 wherein at least one ofsaid distributors comprises a plurality of protruding members, wherebysaid particles are transported in a predetermined direction thereby. 16.The apparatus of claim 15 wherein said protruding members are disposedin the shape of an elliptical planar brush.
 17. The apparatus of claim16 wherein said protruding members comprises a plurality of protrudingpins.